Two rapid, simple (requiring minimal pre-sample preparation), sensitive, and specific assay systems for tocopherols (vitamin E) in small samples of vertebrate and invertebrate tissue -- a rotifer bioassay and spectrofluorometry -- will be improved and analyzed by determining: a) the response of the bioassay to tocols, tocotrienols, and related compounds; and b) the applicability of the bioassay and spectrofluorometry for measurements of vitamin E in lipid mixtures and crude lipid fractions. Rotifer bioassays and spectrofluorometirc assays will be used for direct measurements of tocopherol in affected tissues and organs in vitamin E-deficient animals and will be related directly to structural changes observed at the light and electron microscope levels. An unknown, probably new vitamin E compound, present in plants both after cutting and senescence, will be purified and identified. The relative biopotency of this compound will be determined in the rat gestation-resportion assay, and information on the derivation and stability of the compound will be obtained.